diff --git a/lib/tree.rb b/lib/tree.rb
index c0d4b51..8dcb030 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -1,4 +1,16 @@
+# bst allow efficient store + update  a sorted, changing dataset
+# trees are nonlinear data structures made of nodes that hold data
+# nodes connected by edges that define a parent + child relationship
+# first node = root node (zero or more child nodes) + is parent node of left & right children
+# each node has 0 or 2 children
+# filled from left to right
+# can have multiple subtrees
+# leaf nodes = nodes w/ 0 children
+
+ 
+
 class TreeNode
+
   attr_reader :key, :value
   attr_accessor :left, :right
 
@@ -10,57 +22,66 @@ def initialize(key, val)
    end
 end
 
+ 
+
 class Tree
   attr_reader :root
+
   def initialize
     @root = nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
-  def add(key, value)
-    raise NotImplementedError
+ 
+
+  # Time Complexity:
+  # Space Complexity:
+
+  # add a value to
+  def add(node, value)
+    if node.value == value
+      return node
+    elsif value < node.value
+      insert(node.left, value)
+    elsif value > node.value
+      insert(node.right, value)
+    else
+      return node = Node.new(value)
+    end
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
+
+  # find a given node
+
   def find(key)
     raise NotImplementedError
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
+
   def inorder
     raise NotImplementedError
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
+
   def preorder
     raise NotImplementedError
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
+
   def postorder
     raise NotImplementedError
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
-  def height
-    raise NotImplementedError
-  end
+  # Time Complexity:
+  # Space Complexity:
 
-  # Optional Method
-  # Time Complexity: 
-  # Space Complexity: 
-  def bfs
+  def height
     raise NotImplementedError
-  end
-
-  # Useful for printing
-  def to_s
-    return "#{self.inorder}"
-  end
-end
+  end
\ No newline at end of file